Factors such as a Doppler effect, a central frequency offset (CFO), and phase noise may cause a phase error to data signal reception in a communications system, resulting in performance degradation or even failure of the communications system. To resolve this technical problem, a transmit end device may insert a phase tracking reference signal (PTRS) into a data signal. A receive end device first estimates a phase error of the PTRS, and then obtains a phase error of the data signal through operations such as filtering and/or interpolation, thereby implementing phase error compensation for the data signal.
In a communications system, a peak-to-average power ratio (PAPR) of a single carrier is relatively low, and therefore, a single carrier may be used for an uplink waveform. However, during data signal transmission using a single carrier, if a PTRS is inserted into a data signal, a PAPR of the communications system may be increased, and therefore an advantage of the single carrier cannot be well utilized.